We investigate subregion holographic complexity in the context of
renormalization group flow geometries. We use both the Poinca\'re slicing and
the Janus ansatz as holographic duals to renormalization group flows in the
boundary conformal field theory. In the former metric, subregion complexity is
computed for a disc and a strip shaped entangling region. For the disc shaped
region, consistent emergence of length scales for flow to the deep infra-red is
established. For strip shaped regions, we find that complexity cannot locate
holographic phase transitions in a sharp domain wall scenario. For smooth
domain walls, we find that the complexity might be an indicator of such phase
transitions, and give numerical evidence that its derivative changes sign
across a transition. Finally, the complexity is computed numerically using the
Janus ansatz.Comment: 1 + 22 pages, 14 figures, substantially modified draf